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- Chernov, S. V., et al.
(author)
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Sr2GaScO5, Sr10Ga6Sc4O25, and SrGa0,75Sc0,25O2,5: a Play in the Octahedra to Tetrahedra Ratio in Oxygen-Deficient Perovskites
- 2012
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In: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 51:2, s. 1094-1103
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Journal article (peer-reviewed)abstract
- Three different perovskite-related phases were isolated in the SrGa(1-x)Sc(x)O(2.5) system: Sr(2)GaScO(5), Sr(10)Ga(6)Sc(4)O(25), and SrGa(0.75)Sc(0.25)O(2.5), Sr(2)GaScO(5) (x = 0.5) crystallizes in a brownrnillerite-type structure [space group (S.G.) Icmm, a = 5.91048(5) angstrom, b = 15.1594(1) angstrom, and c = 5.70926(4) angstrom] with complete ordering of Sc(3+) and Ga(3+) over octahedral and tetrahedral positions, respectively. The crystal structure of Sr(10)Ga(6)Sc(4)O(25) (x = 0.4) was determined by the Monte Carlo method and refined using a combination of X-ray, neutron, and electron diffraction data [S.G. I4(1)/a, a = 17.517(1) angstrom, c = 32.830(3) angstrom]. It represents a novel type of ordering of the B cations and oxygen vacancies in perovskites. The crystal structure of Sr(10)Ga(6)Sc(4)O(25) can be described as a stacking of eight perovskite layers along the c axis ...[-(Sc/Ga)O(1.6)-SrO(0.8)-(Sc/Ga)O(1.8)-SrO(0.8)-](2 center dot center dot center dot) Similar to Sr(2)GaScO(5), this structure features a complete ordering of the Sc(3+) and Ga(3+) cations over octahedral and tetrahedral positions, respectively, within each layer. A specific feature of the crystal structure of Sr(10)Ga(6)Sc(4)O(25) is that one-third of the tetrahedra have one vertex not connected with other Sc/Ga cations. Further partial replacement of Sc(3+) by Ga(3+) leads to the formation of the cubic perovskite phase SrGa(0.75)Sc(0.25)O(2.5) (x = 0.25) with a = 3.9817(4) angstrom. This compound incorporates water molecules in the structure forming SrGa(0.75)Sc(0.25)O(2.5)center dot xH(2)O hydrate, which exhibits a proton conductivity of similar to 2.0 x 10(-6) S/cm at 673 K.
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- Fedotov, Pavel V., et al.
(author)
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Optical Study of Nanotube and Coronene Composites
- 2013
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In: Journal of Nanoelectronics and Optoelectronics. - : American Scientific Publishers. - 1555-130X .- 1555-1318. ; 8:1, s. 16-22
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Research review (peer-reviewed)abstract
- A novel nanomaterial, graphene nanoribbons encapsulated inside single-walled carbon nanotubes (GNR@SWNT), was studied by combined optical methods. This nanomaterial was found to have a bright photoluminescence both in IR and UV-Vis spectral ranges. Its spectral features have a complicated resonant structure different from the features of initial components: coronene molecules and SWNTs. The encapsulation ability appears to correlate strongly with the geometry of SWNTs. A weak interaction between nanotube walls and encapsulated species has been discovered: no evidence of charge or energy transfer has been registered.
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- Bragina, O. D., et al.
(author)
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A direct comparison of the diagnostic efficacy of alternative scaffold- based radiopharmaceuticals [99mTc]Tc-ADAPT6 and [99mTc]Tc-(HE)3-G3 in patients with HER2-positive breast cancer
- 2023
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In: BYULLETEN SIBIRSKOY MEDITSINY. - 1682-0363 .- 1819-3684. ; 22:3, s. 6-13
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Journal article (peer-reviewed)abstract
- Aim. To perform a direct comparison of the diagnostic efficacy of [(99)mTc]Tc-ADAPT6 and [(99)mTc]Tc-(HE)3-G3 in HER2-positive breast cancer patients before the systemic treatment.Materials and methods. The study included 11 patients with HER2-positive breast cancer (T1-4N0-2M0-1) before the initiation of systemic treatment. All patients underwent a radionuclide examination with [(99)mTc]Tc-ADAPT6 and [(99)mTc]Tc-(HE)3-G3 with the interval of 3-4 days. Single-photon emission computed tomography (SPECT) /computed tomography (CT) was performed 2 and 4 hours after [(99)mTc]Tc-ADAPT6 and [(99)mTc]Tc-(HE)3-G3 administration, respectively.Results. The analysis of [(99)mTc]Tc-ADAPT6 and [(99)mTc]Tc-(HE)3-G3 distribution showed their high uptake in the kidneys and liver. Breast tumors were visualized in all cases. The average tumor uptake of [(99)mTc]Tc-ADAPT6 was 4.7 +/- 2.1, which was significantly higher than in the [(99)mTc]Tc-(HE)3-G3 injection (3.5 +/- 1.7) (p < 0.005, paired t-test). The tumor-to-background ratio (15.2 +/- 7.4 and 19.6 +/- 12.4, respectively) had no statistical differences in both cases (p > 0.05, paired t -test). Liver metastases were visualized in patients 1 and 5 and corresponded to the projection of metastases according to contrast-enhanced abdominal CT. The accumulation of [(99)mTc]Tc-ADAPT6 and [(99)mTc]Tc-(HE)3-G3 in the projection of metastases in both cases was significantly higher compared to the primary tumor (1.3 and 1.7 times higher in patient 1; 2.2 and 3.5 times higher in patient 5, respectively).Conclusion. Both [(99)mTc]Tc-ADAPT6 and [(99)mTc]Tc-(HE)3-G3 demonstrated the diagnostic efficacy in visualizing a primary HER2-positive tumor in breast cancer patients. However, [(99)mTc]Tc-ADEPT6 had higher accumulation values, which makes it a more promising diagnostic agent.
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| 6. |
- Bragina, O. D., et al.
(author)
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Possibilities of radionuclide diagnostics of Her2-positive breast cancer using technetium-99m-labeled target molecules : the first experience of clinical use
- 2021
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In: Bûlleten' sibirskoj mediciny. - : Siberian State Medical University. - 1682-0363 .- 1819-3684. ; 20:1, s. 23-30
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Journal article (peer-reviewed)abstract
- Background. The main purpose of the Her2/neu status determination in clinical practice is to determine the indications for the appointment of targeted therapy. The main methods for detecting the Her2/neu status are the immunohistochemical method (IHC) and the fluorescence in situ hybridization (FISH); however, despite their widespread use, they have a number of significant disadvantages. Over the past few years, radionuclide diagnostics using a new class of alternative scaffold proteins that meet all the requirements for optimal delivery of radionuclides to tumor cells has become widespread.Aim. To study the possibility of clinical use of a radiopharmaceutical based on technetium-99m-labeled target molecules for the diagnosis of breast cancer with the Her2/neu overexpression in humans.Materials and methods. The study included 11 patients with breast cancer (T1–4N0–2M0) before systemic therapy: 5 with Her2/neu overexpression; expression of the marker was not detected in 6. In all cases, morphologicaland immunohistochemical studies were performed. In case of Her2/neu 2+, FISH analysis was performed. The radiopharmaceutical was prepared immediately before administration, after which it was slowly injected intravenously into the patient. Scintigraphic studies in the “WholeBody” mode and SPECT of the chest organs were performed 2, 4, 6 and 24 hours after injection.Results. Radiochemical yield, radiochemical purity and activity before administration were (80 ± 4)%, (98 ± 1)% and (434 ± 19.5) MBq, respectively. The greatest uptake by normal organs was observed at a time interval of 6 hours in the kidneys and at a moderate activity in the liver and lungs at the same time interval. The organ with the highest absorbed dose was the kidneys; significant accumulation was also detected in the adrenal glands, gallbladder, liver, pancreas and spleen. The smallest accu mulation of the studied drug was observed in the brain (0.001 ± 0.000) mGy and skin (0.001 ± 0.000) mGy. The effective dose was (0.009 ± 0.002) mGy. The difference between tumors with positive and negative Her2-neu expression was found at all time points. In this case, the best indicator was determined after 2 hours of drug injection (р < 0.05).Conclusion. Based on the results obtained, it can be indicated that the investigated radiopharmaceutical can be considered as a new additional method for the diagnosis of Her2-positive breast tumors.
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| 8. |
- Chernov, Alexander I, et al.
(author)
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Optical properties of graphene nanoribbons encapsulated in single-walled carbon nanotubes
- 2013
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In: ACS Nano. - : American Chemical Society (ACS). - 1936-0851 .- 1936-086X. ; 7:7, s. 6346-6353
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Journal article (peer-reviewed)abstract
- We report the photoluminescence (PL) from graphene nanoribbons (GNRs) encapsulated in single-walled carbon nanotubes (SWCNTs). New PL spectral features originating from GNRs have been detected in the visible spectral range. PL peaks from GNRs have resonant character, and their positions depend on the ribbon geometrical structure in accordance with the theoretical predictions. GNRs were synthesized using confined polymerization and fusion of coronene molecules. GNR@SWCNTs material demonstrates a bright photoluminescence both in infrared (IR) and visible regions. The photoluminescence excitation mapping in the near-IR spectral range has revealed the geometry-dependent shifts of the SWCNT peaks (up to 11 meV in excitation and emission) after the process of polymerization of coronene molecules inside the nanotubes. This behavior has been attributed to the strain of SWCNTs induced by insertion of the coronene molecules.
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| 9. |
- Nagirnyi, V, et al.
(author)
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Iron-related luminescence centers in ZnWO4 : Fe
- 2002
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In: Radiation Effects and Defects in Solids. - : Informa UK Limited. - 1042-0150 .- 1029-4953. ; 157, s. 1123-1123
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Journal article (peer-reviewed)abstract
- A systematic spectroscopic study of single ZnWO4 :Fe crystals with different iron concentrations has been performed under excitation by ultraviolet light, by synchrotron radiation or under photostimulation by near-infrared light. The luminescence of Fe3+-related centres has been studied. It is shown that iron centres of different types efficiently promote the formation of crystal defects at low temperatures. Electrons and holes can be trapped near Fe2+ or Fe3+ ions, which is further revealed in phosphorescence, thermostimulated or photostimulated luminescence. At room temperature the main effect of iron impurity is to reduce the light yield of a ZnWO4 scintillator.
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